Tacrolimus is a medication primarily used to prevent organ rejection in transplant patients, such as those receiving a kidney or liver transplant. It works by suppressing the immune system, which helps the body accept the new organ without attacking it. Tacrolimus is often prescribed in combination with other immunosuppressive drugs to enhance its effectiveness. This medication is available in various forms, including capsules and topical ointments. When used topically, tacrolimus can treat skin conditions like eczema by reducing inflammation and itching. Patients taking tacrolimus must be monitored regularly for potential side effects, including kidney issues and increased risk of infections.